Non Consistent Performance

[S76]

I've been battling this issue since last year, and am running out of money. I'll try to explain as best I can.

Normal cruise, say 60 MPH. If you let off on the throttle, and then bring it back on slowly the engine will start to pull a little (not as much as it should) but then at 1/8 throttle it will spring to life. When it does this I can notice my fuel mileage dropping off by about 3 MPG. It will stay in this "mode" for maybe 15 minutes or so and then go back to operating normally.

When it goes back to normal the throttle response returns to nice and crisp with very little throttle needed to maintain cruise conditions. It will stay good for a while and then revert back to the above scenario. It spends about 50% of the time in the bogging mode and 50% in the normal mode. Note: What I am perceiving is not huge. Some people may not notice, but it is rather pronounced once you recognize it and look for it.

There are no error codes of course and it has been doing it since last year so gas it out.

History

Throttle Sync done. although that can't be it because the problem is not consistent

Valves done, CCT and chain 10K ago, though that can't be it because the problem is not consistent

TPS changed a couple weeks ago and made no difference ( I really thought that was going to fix it even though I tested it numerous times with no faults.)

ECU changed, did not cure the problem

Currently running a PCIII with 4 clicks of positive Barbarian mod added and the plugs are still very white. Without the 4 clicks of Barbarian mod the bike still hesitated. The PCIII map is the original for this bike. Bike is stock, no mods. O2 unplugged.

I suspect it is something to do with the fuel mixture mapping. I also suspect the times it has poor response it is a lean stumble that I am experiencing.

So I guess my question is, what other sensors are most likely to influence fuel mixture.

Ambient temp sensor

Water temp sensor

Both

Neither

I wish I knew the logic in the ECU computer.

And where is the PA (pressure altitude) sensor? Is it in the ECU? I need to start running these things down.

Is it possible the PCIII is messed up? It is getting power and lights up.

Also, unrelated, if you have a crank sensor, why do you need the cam speed sensor?

Sorry for the length. Thanks in advance for any insight.

 

[Fred W]

Bob,

Did it do it with the PC disconnected (or before PCIII)?

Since it appears to be an intermittent fueling problem, I would have first suspected the ECU, but you ruled it out on me. The PCIII would also be suspect.

 

[RadioHowie]

First thing I'd suggest is disconnecting the PCIII just to get it out of the "mix". If it was a carbureted bike, I'd say your pilot jets were too small, causing a lean "stumble" on re-accel after losing revs on decel. Wonder if your PCIII is mapped too lean in the lower throttle-input range?

Also, many reports of bad PCIII grounds causing similar sounding issues.

 

[Tree Doc]

Longshot....

I had some pretty oddball ignition miss going on. Felt like valve issue as I could feel it through the bars going through low rpms. Also had really unusual throttle control at times. Did the TBS, new Iridiums, TBS again....head scratch.

Stumbled on to 03HiYoSilver's connector cleaning tip and did it......PROBLEMS SOLVED.

Give it a shot. Ya got nothing to lose!

https://www.fjrforum.com/forum/lofiversion/...php/t22734.html

 

[RadioHowie]

Longshot....
I had some pretty oddball ignition miss going on. Felt like valve issue as I could feel it through the bars going through low rpms. Also had really unusual throttle control at times. Did the TBS, new Iridiums, TBS again....head scratch.

Stumbled on to 03HiYoSilver's connector cleaning tip and did it......PROBLEMS SOLVED.

Give it a shot. Ya got nothing to lose!

https://www.fjrforum.com/forum/lofiversion/...php/t22734.html

I was gonna go there, too, but S76 has a Gen II. Does the same connector apply???

 

[Checkswrecks]

Normal cruise, say 60 MPH. If you let off on the throttle, and then bring it back on slowly the engine will start to pull a little (not as much as it should) but then at 1/8 throttle it will spring to life. When it does this I can notice my fuel mileage dropping off by about 3 MPG. It will stay in this "mode" for maybe 15 minutes or so and then go back to operating normally.
When it goes back to normal the throttle response returns to nice and crisp with very little throttle needed to maintain cruise conditions. It will stay good for a while and then revert back to the above scenario. It spends about 50% of the time in the bogging mode and 50% in the normal mode. Note: What I am perceiving is not huge. Some people may not notice, but it is rather pronounced once you recognize it and look for it.

That it doesn't happen and remain makes me think it's not heat related. That and the on/off nature makes it sound like a loose internal connection, not something from your throttle body sync, valves, CCT, or other adjustments. Also not like the corroded connector problems in the Gen1 bikes, as that stumbling remained pretty constant adn didn't give the mpg hit (at least not in mine). I'd be thinking electronic somewhere, but not a mapping problem in the ECU. Mapping issues would be continuous.

There are no error codes of course ...

This means that it's not a hard failure and is on the sensing side of a sensor, not the portion of the sensors that the computer is able to monitor.

My first guesses would be the TPS & O2 sensor, as they have the toughest environments, and ECU. But you said that you changed the TPS and ECU, plus unplugged the O2. If "unplugged" refers to the electrical connector for the sensor, what happens when you re-connect it?

What about taking the PCIII out of the equation, as suggested already? It's the most prominent thing that is not stock and what you describe as symptoms would easily fit for a loose circuit in an aftermarket product. It'd be my next step.

You've mentioned the sensors for air temp, water temp, crank, and cam speed. I'm not sure on the Feej which sensor will do the job, but there'll also be one for knocking/pinging. Unfortunately, the "no error codes" implication of something failing on the non-monitored internal side of a sensor means that if you get to these sensors, they will need to be replaced one by one. You can see if temp sensors respond with an oven or pan of water on the stove, but it'd be pretty tough to simulate the bike's constantly changing temps and vibrations that way.

There are a couple of non-electrical items to think of. Is your gas tank vent clear and not have a bit of crud randomly roll over the port? You've looked closely at the hoses under the tank and none are kinked or pinched?

 

[BkrK12]

My personal experience with PC III is that if there is a PC ground problem, the bike doesn't run at all. OTOH, with a PC you shouldn't have to bump up the CO levels at all. The fact that you are at +4, with the PC, and the plugs are showing a lean condition would seem to indicate that you are getting no help from the PC. Have you checked the cell content of the map you're running? It almost sounds like you have the "Zero map" loaded.

Another idea would be to go to the Dynojet site to see if you are running the latest firmware. Someplace, in the not too distant past, there was a firmware update you could download off their site.

Also, someone - I think it was Daily Commuter - had to actually return his PC to Dynojet and get a new one. Can't remember what his problem was. But, you can check his old Topics.

EDIT: It was Daily Commuter and you can find it as "PC III not communicating".

 

[twodogs]

It almost sounds like you have the "Zero map" loaded.

I give this a "bingo!".

As I remember, it's very easy for the PC to revert to the zero map if the map installation instructions are not followed to the letter. Also, if you just installed it without installing a map, you are running no map.

 

[Fred W]

A zero map with the O2 disconnected would probably result in some very strange fueling.

 

[S76]

Thank you all for your input. Some really good ideas there.

Today I checked the PCIII map and it was indeed the stock map for an 06. So I created another map by adding +2 to every one of the trim values.

The bike ran really well after that. I could not detect my little issue any more. I guess that sort of confirms the suspected lean condition. I think the bike was right on the verge of a lean stumble, sometimes doing it and sometimes not.

What I still do not understand, is why do I have to run this bike with +2 on the PCIII and 4 clicks of BJM? After todays adjustment the fuel average readout was indicating 48 MPG running 40/50 MPH on back roads, which is pretty much where it was.

Can it be the Connecticut gas with the 10% alcohol is the problem? The stock map was developed in Arizona I believe. Do they use 10% out there? I do know the alcohol leans the mixture substantially.

I guess the next step to learn more, as suggested, is to get the PCIII out of the picture and see how it runs in stock trim.

Thanks for your insight.

 

[BkrK12]

The Fuel Avg readout is very optomistic with the PC III installed. The onboard computer doesn't know you have a PC pumping extra fuel into the mix. You have to calculate it the old fashioned way to get an accurate number

 

[S76]

The Fuel Avg readout is very optomistic with the PC III installed. The onboard computer doesn't know you have a PC pumping extra fuel into the mix. You have to calculate it the old fashioned way to get an accurate number

Absolutely correct. I need to do an actual measurement to get a real number. What I have noticed though is when the bike is running lousy those numbers do drop off a little, and when it is running good they will rise a little.

 

[Harald]

Thank you all for your input. Some really good ideas there.
Today I checked the PCIII map and it was indeed the stock map for an 06. So I created another map by adding +2 to every one of the trim values.

Did you actually look at the map on your computer? I'm curious because I'm running the stock map for my 07, but this is not a zero map. It's confusing because by saying "stock" they are referring to a bike without aftermarket air filter or pipe (ie - STOCK intake and exhaust). By looking at the stock map, Dynojet has still modified the map for better performance. A zero map is purely using the bikes ECU for fueling with no modification.

 

[Auburn]

I'm running Useless Pickle's smoothness map on my 06. You might try that and see if works for you. I like the map for my bike.

 

[Fred W]

That should really work fine, so long as you both (all) have not made any major intake or exhaust mods. I'm running a custom map that was sent to me by another 2005 owner that had a custom map made up, and his bike (like mine) is all stock. The map works fine on both of our machines, and I've taken the liberty to forward it to some others who have also not complained.

The real key is in getting a dyno shop that will listen to your request / needs and tune the appropriate PCIII cells, and not just the top end (where all the groovy HP is).

 

[S76]

Thank you all for your input. Some really good ideas there.
Today I checked the PCIII map and it was indeed the stock map for an 06. So I created another map by adding +2 to every one of the trim values.

Did you actually look at the map on your computer? I'm curious because I'm running the stock map for my 07, but this is not a zero map. It's confusing because by saying "stock" they are referring to a bike without aftermarket air filter or pipe (ie - STOCK intake and exhaust). By looking at the stock map, Dynojet has still modified the map for better performance. A zero map is purely using the bikes ECU for fueling with no modification.

Yes, you are right. When I checked I found the Map that DynoJet originally made for the 06 FJR in stock trim. The table was full of values. If it was a zero map it would not have any numbers in it. I added 2 points to every value and loaded it.

Rode to work today and the bike ran like a raped ape in a forest fire. No hesitation. I hate to quit while I'm ahead, it's never been my style, but I may just leave well enough alone.

 

[twodogs]

Yes, you are right. When I checked I found the Map that DynoJet originally made for the 06 FJR in stock trim. The table was full of values. If it was a zero map it would not have any numbers in it. I added 2 points to every value and loaded it.
Rode to work today and the bike ran like a raped ape in a forest fire. No hesitation. I hate to quit while I'm ahead, it's never been my style, but I may just leave well enough alone.

Now, if you really want to know if the +2 made the difference, take them out, re-load and see what happens. The resulting performance will determine whether the stock map was functioning previously. OTOH, as you say, it runs now so it may be best to leave well enough alone.

 

[JamesK]

I'm running Useless Pickle's smoothness map on my 06. You might try that and see if works for you. I like the map for my bike.

+1, the Useless Pickle's smoothness map is great, after trying that map I had no reason to spend the $$$ for a Dyno, good combination of performance and good MPG.